Pregnant Drew Barrymore, 37, picked a summer date for her California vows to art consultant Will Kopelman, 34, "because she wants to get married before the baby comes, but doesn't want to be huge," a pal tells the new issue of Us Weekly (out now).

After taking their romance public in February 2011, Us exclusively confirmed that Kopelman popped the question in Sun Valley, Idaho over the holidays, giving Barrymore a radiant-cut Graff diamond just under 4 carats.

The "Big Miracle" actress and her beau recently returned from Paris, where she chose a Chanel wedding dress. (Kopelman's dad is the former head of the fashion house.) "Drew met with his staff and had the first of many fittings," the pal says.